Difficulty of swallowing, called dysphagia, leads to aspiration pneumonia which is particularly a big health concern in aging societies. Therefore, prevention and treatment of dysphagia would contribute to extending healthy-life and QOL of elderly people and decreasing healthcare cost. Robotics technologies are expected as one of the effective methods to solve the problem in terms of detecting malfunction in swallowing and recovering swallowing function. The aim of this study is to investigate muscle activity during normal swallowing using mechanomyography (MMG) with PolyVinylidene DiFluoride (PVDF) film which is a ferroelectrics polymer. Measurement of MMG signal during voluntary isometric contraction of the biceps brachii muscle was conducted to confirm whether PVDF film can detect MMG signal. In the experiment, surface electromyography (sEMG) was also measured as a reference to estimate muscle activity for comparison. Then, activities of swallowing muscles during normal swallowing with different volume of bolus were measured using MMG signal. As the result, it was confirmed that swallowing activity can be quantified by the detected MMG signal from different region of neck.